This invention relates generally to a solid state lighting system. Specifically, it relates to the use of solid state solar cell, fuel cell and light emitting diode (LED) technologies with a bi-directional power converter to produce an efficient autonomous lighting system.
Delivery of electric power to remote areas introduces a difficult challenge, as it is both complex and costly to transmit power to these areas. Transmission lines constructed to carry power may be expensive and environmentally undesirable. Distribution from the utility power grid may require the construction of transformers and switch yards, which may be impractical or prohibitively expensive. In addition, mercury vapor lighting as often used for rural and outdoor lighting is less desirable due to public concerns about mercury.
Solid state energy cell technology has been emerging as a useful alternative energy source for electrical equipment. Solar cells are a form of solid state cell technology used to convert light energy into electrical energy. Solid state lighting sources, such as light emitting diode (LEDs), are being used more frequently as the technology advances and becomes more cost efficient.
Solar cells are increasingly being used as clean energy sources for many different applications, especially in rural areas. Typically, a power converter is used to convert the solar cell current to the voltage/current waveform for the end user""s equipment. For lighting applications, the energy collected from solar cell panels during the daytime is stored in a battery pack after passing through a power converter. During the nighttime, the energy stored in the battery is released to lights through another different power converter. The use of two power converters requires independent systems with separate magnetic and semiconductor components, increasing cost and complexity.
It would be desirable, therefore, to provide an autonomous solid state lighting system with a single power converter that overcomes the above disadvantages.
One aspect of the present invention provides an autonomous solid state lighting system suitable to supply power in rural areas and for outdoor lighting.
Another aspect of the present invention provides an autonomous solid state lighting system to supply power independent of the power grid.
Another aspect of the present invention provides an autonomous solid state lighting system to provide lighting without the use of mercury.
Another aspect of the present invention provides an autonomous solid state lighting system using a single power converter to reduce cost and complexity.
Another aspect of the present invention uses an alternative energy source, such as a fuel cell.
The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.